There are in existence various mechanisms for connecting and disconnecting shoulder belts from the rear window or door frames of automotive vehicles such as station wagons, for example, when it is desirable to remove the back seat therefrom for hauling purposes. Many of these include keyhole openings and/or leaf spring coupling components, but many easily removable types do not include a positive locking action.
Two coupling arrangements are shown and described in Takada Pat. No. 4,334,701. One embodiment includes a keyhole opening for attachment of a plate carrying a shoulder belt to a bolt-like coupling pin with resiliently deformable tangs which spring back to engage the edge of the plate once the shank portion of the pin enters the smaller portion of the keyhole opening, thus preventing the coupling from being disconnected during normal use.
Another embodiment of the No. 4,334,701 patent includes a pair of plates and a leaf spring. One plate includes a bolt-like coupling pin and a T-shaped projection, while the second plate includes a keyhole opening and a contoured slot. The leaf spring is connected by rivets to the latter plate, and is deflected to allow the head of the pin to pass through the larger portion of the keyhole opening. Once the shank of the pin enters the smaller portion of the keyhole opening, the leaf spring springs back to retain the pin. In the meantime, the T-shaped projection has entered the contoured slot, serving to limit the pivoting of the second plate on the pin.
Ogawa Pat. No. 4,473,243 discloses a three-plate arrangement wherein one plate includes a keyhole opening, a second plate includes a bolt-like anchor pin, and the third plate is resiliently deformable but includes an opening for receiving the head of the pin and a small projection for selectively entering small holes formed in the second plate to prevent relative rotation between the plates.